No one posted this and I can't post the whole article (kind of pointless as most of the stuff already happened this week anyway) but since so many mentioned how they are having trouble understanding Nick's motivation for what he is doing to Melanie, I thought I would post this quote from Blake in which he addresses the issue. The article is from the 11/11/08 SOD.

Here it is: "One by one, she's alienated a lot of people, and since Nick is the only one who is there for her, he needs to make sure she needs him like he needs her, and he exploits her vulnerability," explains Berris of his alter ego's motivation. "Being able to be there for her outweighs how hard it is for him to see her in this horrible situation. He gets to spend more time with her and be her hero."

He goes on to say: "There's a lot of emotion clouding Nick's clarity of mind, but I think what he wants is to be with Melanie and he's going to do anything he can to make that happen."

Sounds reasonable to me. Hope this provides some insight to those who were having issues with his motivation behind his actions in regards to the letters and phone call.